Optimisation of Wheelset Maintenance using Whole System Cost Modelling

Transcription

1 Optimisation of Wheelset Maintenance using Whole System Cost Modelling Adam Bevan, Paul Molyneux-Berry University of Huddersfield Steve Mills Rail Safety & Standards Board Andy Rhodes, Daniel Ling Serco V/T SIC Vehicle / Track System Interface Committee

2 Overview Background Vision of VTISM Wheelset Maintenance Strategy Damage rates and WPDM Wheelset Costs Whole System Costs Summary Acknowledgements

3 Background Wheelset maintenance and renewal activities account for a large proportion of a fleets whole-life costs Influenced by a large number of factors: Depot constraints Wheel tread damage Fleet availability Vehicle design Optimisation of maintenance and renewal regimes will help to increase wheelset life and reduce costs

4 Background Tools currently exist for prediction of track damage, replacement and maintenance costs Whole Life Rail Model (rail RCF & wear) Track-Ex (NR decision support tool) VTISM (links vehicle-track characteristics to track costs) Stage 2 development of VTISM enhanced the rolling stock modelling capabilities Strategic planning of wheelset maintenance and renewal activities Examine benefits and cost impact of a range of different scenarios Optimise wheelset management strategies These enhancements go some way to determining the whole life costs for the complete system (vehicle-track)

5 Vision of VTISM Vehicle Maintenance and Design Changes Vehicle-Track Interaction & Forces Wheelset Inspection, Maintenance & Renewals Wheel Profile Damage Model Whole Life Rail Model Volumes / Costs Track Maintenance Improvements Track Inspection, Maintenance & Renewals Volumes / Costs

6 Vision of VTISM Prediction of wheel/rail forces Vehicle Maintenance and Design Changes Wheelset Inspection, Maintenance & Renewals Volumes / Costs Define asset data, initial conditions and limits Vehicle-Track Interaction & Forces Wheel Profile Damage Model Whole Life Rail Model Track Maintenance Improvements Track Inspection, Maintenance & Renewals Volumes / Costs

7 Vision of VTISM Vehicle Maintenance and Design Changes Prediction of rail wear and RCF damage Vehicle-Track Interaction & Forces Wheelset Inspection, Maintenance & Renewals Wheel Profile Damage Model Whole Life Rail Model Volumes / Costs Define inspection, maintenance and renewal strategy Evaluate asset condition over time and trigger track inspection, maintenance and renewals (T-SPA) Track Maintenance Improvements Track Inspection, Maintenance & Renewals Volumes / Costs Determine whole life costs

8 Vision of VTISM Define inspection, maintenance and renewal strategy Evaluate asset condition over time and trigger wheel inspection, maintenance and renewals (W-SPA) Prediction of the rate of wheel wear and RCF damage Vehicle Maintenance and Design Changes Vehicle-Track Interaction & Forces Wheelset Inspection, Maintenance & Renewals Wheel Profile Damage Model Whole Life Rail Model Volumes / Costs Track Maintenance Improvements Track Inspection, Maintenance & Renewals Volumes / Costs Determine whole life costs

9 Wheelset Maintenance Strategy Inspection Strategy Applied if mileage since last inspection is greater than the relevant inspection interval Wheel Turning Strategy Triggered if condition reaches a predefined limit (i.e. flange thickness is less than the minimum permitted flange thickness) Wheelset Replacement Strategy Triggered if condition reaches a predefined limit (i.e. wheel diameter is less than the minimum diameter for running

10 Damage Rates Rates of damage are included to describe how the attributes of the wheel deteriorate over time Tread/flange wear Change in conicity RCF damage Probability of flats Compared with pre-defined limits - trigger maintenance or renewal activity This information can be obtained from observation data Alternatively, the WPDM can be used to predict the damage rates

11 WPDM Wheel Profile Damage Model (WPDM) is a standalone tool for the prediction of deterioration rates of the wheel tread Uses VAMPIRE vehicle dynamics simulation software to predict wear and RCF damage WPDM methodology Characterises a vehicle s route diagram in terms of parameters which influence wheel damage Predicts wheel-rail forces for the chosen route conditions using vehicle dynamics simulations Post-process the calculated wheel-rail forces to predict the formation of wear (Archard model) and RCF (Tγ-damage model) on the wheel Plot and save the results for use within VTISM and WMM

12 Predicted Wheel Wear

13 Analysis Scenarios Mileage-based turning regime (Base Case) Turning interval set to 140,000 miles to represent current practice Reduced mileage-based turning interval Turning interval reduced to 100,000 miles to represent a little and often turning regime Condition-based turning regime Turning triggered by the condition of the wheelset only Lubrication strategy Coefficient of friction at the flange contact was reduced to µ=0.1 Inspection and maintenance of the lubrication system included Includes modified wear and RCF damage rates for all wheelset types Modified primary yaw stiffness Includes modified wear and RCF damage rates for all wheelset types

14 Wheelset Whole Life Costs

15 Wheelset Whole Life Costs Reduced Turning Interval Increase in mileage-based turning Reduction in turning for damage

16 Wheelset Whole Life Costs Reduced Turning Interval Increase in mileage-based turning Reduction in turning for damage Condition-based Turning Increase in turning for damage and parity No mileage-based turning

17 Wheelset Whole Life Costs Reduced Turning Interval Increase in mileage-based turning Reduction in turning for damage Condition-based Turning Increase in turning for damage and parity No mileage-based turning Primary Yaw Stiffness Increase rates of damage Increase in turning for damage

18 Wheelset Whole Life Costs Reduced Turning Interval Increase in mileage-based turning Reduction in turning for damage Condition-based Turning Increase in turning for damage and parity No mileage-based turning Primary Yaw Stiffness Increase rates of damage Increase in turning for damage Lubrication Reduction in damage rates Increase in number of wheelsets achieving mileage-based turning

19 Optimised Wheel Turning Interval Total costs for varying wheel turning interval

20 Material Loss at Turning Low mileages cut depth is governed by the amount of material loss required to restore the profile shape Higher mileages similar cut depth to restore profile, but additional material removed due to RCF damage Running Distance 61,000 mile 0.6mm diameter loss due to wear 2.5mm cut depth to restore profile New P8 profile Worn profile Profile after turning RCF damage depth Optimum turning interval Running Distance 178,000 mile 2.0mm diameter loss due to wear 2.7mm cut depth to restore profile

21 Whole System Costs Increased intervals between wheel turning may result in a cost benefit to vehicle operators/maintainers But increases in wheel/rail conformality may result increasing the probability of RCF damage on the track To reduce whole system costs (vehicle-track) it is therefore important to optimise both sides of the interface Whole Life Costs ( ) Wheelset Track Min. Both Min. Wheelset Turning Interval (miles)

22 Cum. Distribution % Increase (+) or Deacrease (-) in Cost Relative to Base Case Cum. Distribution Track-Wheelset Costs 1 Distribution of Flange Height Mileage-based (140k mile) Mileage-based (100k mile) Condition-based Lubrication (140k mile) Primary Yaw Stiffness (140k mile) Flange Height (mm) Distribution of Flange Thickness Mileage-based (140k mile) Mileage-based (100k mile) Condition-based Lubrication (140k mile) Primary Yaw Stiffness (140k mile) 45% 35% 25% 15% 5% -5% -15% -25% -35% -45% Track Wheelset 100k mile 160k mile Condition-based Lubrication Primary Yaw Stiffness Flange Thickness (mm)

23 Summary New tools have been developed which allow users to: Evaluate wheelset whole life costs using fleet asset inventory data, deterioration rates and maintenance regimes Determine annual inspection, maintenance and renewal costs Optimise wheelset maintenance strategy Carry out what if analysis Capabilities of these new tools have been demonstrated by predicting the whole life costs for a typical DMU fleet Cost implications of number of scenarios presented Tools can be used to determine the impact of system changes on both vehicle and track costs potential for reducing whole system costs

24 Acknowledgements The results and findings presented were developed from the RSSB managed rail industry research programme, funded by the Department of Transport V/T SIC Vehicle / Track System Interface Committee For more information: a.j.bevan@hud.ac.uk